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Hi all. I've posted this before, been trying to chase this one day for about 8-9 months! When the Amp warms up after playing about 5 minutes, it give a crackling sound like someone wading up a piece of paper. I looked at all solder joints, one looked weak, so retouched it. I also was a little concerned with #1 tube socket, so replaced that. The sound only happends when I strike a cord or pick a note. It stops as soon as I mute the strings. Any help would be awesome. Thanks

cisco/SoK66, been trying to chase that one down. Long process, but getting through it (lot of solder joints :-).

Amphead4, never thought about the speaker. I had changed the speaker a couple months back to a 1960 Jensen P12Q to keep with the vintage vibe of this amp. It made an amazing difference. I can't recall if thats when the noise started, but it's easy enough to put the one back in that came with the kit. Worth a try! Thanks.

Ok, put my original DRRI C12K in it, basically a brand new speaker, and so far (fingers crossed) it's been playing great. Granted it's only been a couple hours, but usually by now the noise would have already started. Kudos to you all if this is it. I've spent months trying to track this down, tubes, wiring, solder joints, and never once thought about the speaker. I was going for the "as much vintage as I would" approach with the '60 speaker and all JAN NOS tubes. But it actually sounds pretty good with the ceramic in there. I'll play hard for a few more days before I'm convinced and will report back.

take the rear cover off and let the amp warm up to where it's making the noise you're talking about. Put the volumes/tone at the 5-6 mark then take a chopstick and gently push on each input jack individually - where the tip of the guitar cable would contact. I'm assuming that you have the shorting input jacks here - i built a mission kit and that's the type of jack i had. check each one and see if the sound you're talking about is reproduced

I had what sounds like a very similar problem a while ago and it was driving me crazy. If that ends up being a problem there are 2 ways to address it:
1) cut a piece of business card (or any sort of heavy paper-stock) into a small enough piece that it'll fit between the tip of the jack and the part that shorts it out. drag it through there a bunch of times to pick up the grease/metal dust etc.
2) if that doesn't work replace the jack

The speaker is soldered on. I did clean and retention the sockets, actually replaced one that just felt too loose. I've pulled the board out and re-soldered all the contacts. Driving me nut. Before the cracking starts, it's a great sounding amp and I want to play it so bad!

No luck! One thing I did try when it started to make the noise is tap on all the tubes, even though they've been replace Except the rectifier. When I tap that one it goes silent?? I'll try replacing and see if it's that simple

Nope, not that either. Tubes all seem fine. Jacks seem fine. I've re-melted all the solder joints just in case a cold or cracked one. Nada. It must be one of the cap's I guess. Not sure how to check those, might be time to bring it in :-( I live close to Fritz, maybe I can get him to do his magic. Just frustrated, "I" want to fix it, ME, I built it ;-)

Mike62Jazz. Yes I've contacted Mike. It was real hard for him to diagnose given the info I gave him. It's been about a month now that I've written, and now it's even worse. As soon as I power up the amp it starts making the sound, bad! At a loss. How do I check the caps, ohm meter? I'm determined!!!

I just noticed your thread, after searching for some speaker suggestion for my Clark Beaufort.

Anyway FWIW, I had a similar issue with the same type of noise years back with a Fender that ended up being a bad power tube socket that was shorting across contacts. I could also see a small hairline crack in the phenolic.

I think I discovered it by actually seeing a small arcing spark at the socket (leads side) when I had the chassis pulled. Maybe try doing the same in a dark-ish room. It's worth a shot.

If the amp chassis is physically seperated from the speaker cab, does that help (eg a vibration induced bad connection)?

If not, another possibility is parasitic oscillation. The 'crackles' may be blips of oscillation, though it's less likely than a bad contact / dry joint. It's not usually a problem with 5E3, as the gain is fairly low, but it's certainly possible.
Post links to some build photos if possible.
Consider wire runs, especially the OT wires to the output tube plates - keep them tucked well away from anything else, also the wire from the vol controls to V2 grid; maybe replace it with screened cable.
Pete.

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